Equipment for moving step by step a structure carrying out operations supported on a sea-bed or the like

ABSTRACT

A mobile marine platform can be supported on as few as three legs, with the legs vertically and horizontally adjustable so as to move the platform laterally, by surrounding each leg with an inflatable ring. When the ring is inflated, the ring supports the load while the leg is raised and laterally shifted and then lowered again, after which the ring is deflated and the load shifts back to the leg.

United States Patent Van den Kroonenberg EQUIPMENT FOR MOVING STEP BY STEP A STRUCTURE CARRYING OUT OPERATIONS SUPPORTED ON A SEA- BED OR THE LIKE Inventor: l-Ienricus I-Iubertus Van den Kroonenberg, Amsterdam, Netherlands N.V. lndustrieele, Handelscombinatie, Netherlands Filed: March 31, 197! App]. No.: 129,695

Assignee:

Foreign Application Priority Data April 3, 1970 Netherlands ..70/4824 US. Cl ..61/46.5, ll5/9 Int. Cl. ...E02b 17/00, B63b 21/50, B63b 21/56, B63b 15/00 Field of Search ..6l/46.5, 45; 1141.5 D, 43.1; 1 15/9; 37/73 451 Sept. 26, 1972 [56] References Cited UNITED STATES PATENTS l,l34,708 4/1915 Watkins ..1 15/9 3,590,587 7/1971 Smulders ..6l/46.5

Primary Examiner-Jacob Shapiro Attorney-Young & Thompson [57] ABSTRACT A mobile marine platform can be supported on as few as three legs, with the legs vertically and horizontally adjustable so as to move the platform laterally, by surrounding each leg with an inflatable ring. When the ring is inflated, the ring supports the load while the leg is raised and laterally shifted and then lowered again, after which the ring is deflated and the load shifts back to the leg.

4 Claims, 3 Drawing Figures EQUIPMENT FOR MOVING STEP BY STEP A STRUCTURE CARRYING OUT OPERATIONS SUPPORTED ON A SEA-BED OR THE LIKE The invention relates to equipment for moving step by step a structure for carrying out operations, generally comprising a working-platform which is supported at several locations on a seabed or the like, in particular for operations off-shore.

A structure is disclosed in US. Pat. No. 3,590,587, in which the working-surface is supported on the seabed or the like by long columns and in which said columns can be moved in their entirety with respect to the working surface in a vertical and horizontal direction. Therefore this known type of platform must be provided with at least five supporting columns, because if one of the columns is moved in a vertical direction, said column can no longer perform its supporting function, while the working platform under all circumstances has to be supported by at least four columns to maintain its stability.

It is an object of the present invention to provide equipment for moving step by step a working platform which is at several locations supported on the sea-bed or the like, the supports of which are adapted to perform their supporting function under all circumstances, so that the platform can be provide with three supporting columns.

This object is achieved according to the invention by the fact that each of the bed engaging means consists of a relatively short supporting leg by which the platform normally rests on the sea-bed or the like, the arrangement being such that said short supporting leg is movable in a vertical and horizontal direction with respect to the platform, while at least each of said columns is enclosed by an annular, expansible member which is adapted to be in engaging relation with the sea-bed or the like.

If the expansible member is in engaging relation with the sea-bed or the like, said member is adapted to take over the supporting function of the short leg, whereupon said short leg can be retracted with respect to the platform, moved in a horizontal direction and positioned again on the sea-bed or the like, The expansible member can subsequently be withdrawn again, so that the short leg can resume its supporting function, after this operation has been performed for at least one of the other legs, the platform can be moved with respect to the short legs.

The expansible member may advantageously consist of an inflatable, torus-shaped bag, which may or may not be divided into compartments. By the inflation of said bag, it will take over the supporting function of the short leg and when the bag is deflated again, the short leg will resume its supporting function. The bag may be arranged such that also in the non-supporting condition it will come into contact with its bottom part with the sea-bed or the like, so that the short leg will always be enclosed in a sealing relation by the bag and will thus be protected against the scouring action of the water.

The expansible member is preferably connected with the bottom side of an annular structure. It is advantageous to have the mechanism for moving the short leg with respect to the platform incorporated in said annular structure.

The invention will now be further elucidated with reference to the drawings in which a diagrammatic view of an embodiment of the invention applied to one of the long columns of a platform structure are shown. In the drawings:

FIG. I is an elevational view, with parts broken away, of the apparatus according to the present invention;

FIG. 2 is a top plan view of the central portion of the structure shown in FIG. I; and

FIG. 3 is an enlarged fragmentary cross-sectional view of a portion of FIG. I.

A long main column 1 of the platform structure, which is connected at its upper part with the working surface, not shown, is provided at its bottom part with the short supporting leg 2, which is arranged movably in a vertical and horizontal direction in the main column I and is provided near its bottom part with an enlarged portion 3 with which the short supporting leg rests on the sea-bed 4 or the like. The long main column I is furthermore provided with a closed, annular structure 5 by which the short leg 2 is enclosed with a large intervening space, while the bottom part of said structure 5 is provided with a rigid ring 6 supporting in its turn the annular, inflatable bag 7.

In the position shown in the drawing, the short leg 2 carries part of the weight of the working platform, while the annular bag 7 rests with its bottom part against the sea-bed 4 or the like and consequently encloses in a sealing relationship the space around the short leg 2, so that said leg 2 is protected against the scouring action of the water. If it is desired to move the working platform over a short distance, the bag 7 is inflated, so that said bag takes over the supporting function of the leg 2 whereupon said leg 2 can be moved in a vertical direction with respect to the long column 1 and is freed from the sea-bed 4 or the like, whereupon the short leg 2 can be moved in a horizontal direction with respect to the long column 1 and subsequently be lowered to the sea-bed 4 or the like again. The pressure inside the bag 7 is now reduced, on account of which the short leg 2 takes up the full load again, whereupon the long column I and the working surface connected thereto can be moved with respect to the short leg 2.

The mechanism for moving the short column in the lateral and vertical directions is incorporated in the annular body 5 and the column I, so that this mechanism is suitably protected. This mechanism is entirely conventional and comprises a carriage 8 having a bore in which the short leg 2 is slidably received. Carriage 8 is supported by wheels 9 that roll on tracks 10 mounted in housing 11. Housing 11 is mounted for rotation within the inner space of annular body 5 by means of roller bearings 12. A toothed annular member 13 extends about housing 11 and is in engagement with pinion 14 connected with driving means (not shown) mounted inside body 5. Relative vertical movement of leg 2 is effected by cylinder and piston assemblies 15, while relative horizontal movement of carriage 8 is effected by cylinder and piston assemblies 16.

The arrangement according to the invention provides a very simple and yet relatively efficient moving mechanism which can be used, among other things with a structure supported by three long columns. By the arrangement according to the invention only a short, light leg has to be moved, as a result of which the moving mechanism can be of relatively light design.

What I claim is:

moved and then lowered again.

2. Apparatus as claimed in claim 1, said expansible member being a toroidal inflatable bag.

3. Apparatus as claimed in claim I, and an annular structure supporting the expansible member at the top of the expansible member.

4. Apparatus as claimed in claim 3, said moving means being carried by said annular structure.

l l II II t 

1. Apparatus for moving step by step a structure on a sea bed or the like, comprising a relatively short leg by which the structure normally rests on the sea bed or the like, means mounting said leg for vertical and horizontal movement relative to the said structure, means for moving said leg vertically and horizontally relative to the said structure, and an annular expansible member encompassing said leg and so positioned that sAid expansible member when expanded supports said structure to permit said leg to be raised and horizontally moved and then lowered again.
 2. Apparatus as claimed in claim 1, said expansible member being a toroidal inflatable bag.
 3. Apparatus as claimed in claim 1, and an annular structure supporting the expansible member at the top of the expansible member.
 4. Apparatus as claimed in claim 3, said moving means being carried by said annular structure. 